We have a never ending poller process.Once the poller process is hitting the nod

Check the custom.properties file, inside that there is a property for node limits
server.conf.processcommon.MAX_SPAWN_INSTANCES
server.conf.processcommon.MAX_NODE_INSTANCES

Check their values and that will help you in understanding the issue related to your process.

Verify the configuration setting server.conf.processcommon.MAX_NODE_INSTANCES in the custom.properties file.
Reference : forum.appian.com/.../Post-Install_Configurations.html.

In order to be able to execute additional node instances, you may want to increase this setting.

I don't think you should be modifying any limits. This is a very inefficient design and you should be looking to redesign ASAP.

Also if it fits your design, you may be able to use the 'Delete previously completed instances' setting on the sub process, durnig re-execution, to clear out old instances.

One pattern you might want to consider is to use a Timer node as a Start Event of a process model. You can configure to start at the same interval you are using to poll currently, and after you publish the model it will automatically start new process instances at the specified time: forum.appian.com/.../Start_Event_-_Timer.html

This approach has a couple of benefits, including distribution of process instances across all of the execution engines, as well as removing the need to continually increase MAX_NODE_INSTANCES property. There are a couple of things to watch out for however:
-Use a constant to enable/disable the process timer (put in Advanced Options > Timer Conditions) to control it updating in case you ever need to disable for any reason, especially if you have system downtime.
-When there is system downtime, Appian will start instances for every timer that it missed during that interval. You should disable the timer (using the constant) during any planned downtime, and implement a workaround to handle multiple instances at the same time.

@csteward, The issue here is that the timer nodes themselves also accrue instances that count against the MAX_NODE_INSTANCES limit, and you cannot set that type of node to delete previous instances.

Ah yes, that could be worked-around by placing the timer inside it's own sub process as well however - with the delete setting on the sub configuration. But the Start Event timer is a better solution, if it fits the design.

Thanks colins... The start node timer event helped me..cheers